RECEIVED AUGUST 24, l9,X The preparation of four, synthetic geometrical isomers of vitamin A aldehyde (identified as all-trnns, h i s , 2,(i-di-cis, Their ultraviolet absorption spectra, infrared spectra and other physical and chemical properties arc A 2,4-di-cis qtructure An all-trans "a-vitamin A aldehyde" was synthesized from Its properties were different from those of the 6-cis and 2,6-di-cis isomers which excluded the possibility that t h e 6;c-is) is described.given. was preferred for it over a possible 2-trans, 4-cis configuration. a-ionone. latter two compounds might be geometrical isomers of a-vitamin A aldehyde.The configuration of a fifth isomer of vitamin A aldehyde, neoretinene-b, was also studied.In the previous paper in this series2 a synthesis of vitamin A is described by which four crystalline geometrical isomers were prepared. These were identified as the all-trans, 2-cis, 6 4 s and 2,B-di-cis forms, according to the following numbering system CHI CHI \ / CH3

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Conjoined Crystals is the name given to a new food emulsifier whose special properties are associated with its content of glycerol monoester in a stabilized ॅ‐crystalline form (6). It consists of the mixture of crystals formed by cooling a melt containing approximately equal molecular proportion of certain long chain fatty acid monoesters of glycerol and of 1,2‐propanediol. A practical composition contains a blend of glycerol monostearate and 1,2‐propanediol monostearate.Conjoined Crystals disperse readily in water and retain this ability for periods of over a year, a property which appears to be closely associated with their effectiveness in baking and in other applications. This water dispersibility contrasts with the behavior of the usual modification of glycerol monostearate which is difficult to disperse in water.Infrared analysis indicated that the major part of the glycerol monoester in the mixed crystals is in the ॅ‐crystalline modification. Studies by X‐ray diffraction supported this conclusion. Thus, we have consistently associated ready water dispersibility and the ॅ‐form with the enhanced emulsifying ability.

Exposure tests of plated steel were conducted in cooperation with the American Electroplaters' Society and the American Society for Testing Materials, in rural, suburban, industrial, and marine locations. It was found that the thickness of the nickel layer is more important than any other factor. An intermediate layer of copper decreases the protective value of thin deposits but is not detrimental in thick coatings, especially if they are chromium plated. The customary thin chromium coatings (0.